PCT patent application serial number PCT/US07/75485, CALIBRATION OF A MIRROR-SYMMETRIC FIXTURE (Doubrava, et al.) (hereinafter Doubrava '485), herein incorporated by reference, introduces a method for the characterization of a symmetric fixture, hereinafter called SymmetriCal. The SymmetriCal method (Doubrava '485) splits a symmetric THRU structure into mirrored Half-fixtures which may then be mathematically removed from both ports of a 2-port measured structure, leaving only the probe (i.e., the desired device under test (DUT)). What is needed is a method that can handle partially-symmetric fixtures.